1. Field of the Invention
The present invention relates to a multilayer printed board consisting of a signal layer, a power source layer, and a ground layer that are formed one upon another with insulation material being interposed between them. In particular, the present invention relates to a multilayer printed board capable of reducing radio waves emitted from the board.
Many countries have strict regulations to restrict electronic equipment from emitting unwanted radio waves and noise exceeding specific levels.
Electronic equipment needs a technique of minimizing the emission of such radio waves.
2. Description of the Related Art
To reduce radio waves emitted from an electronic apparatus, prior arts provide the apparatus with a structure for entirely shielding the apparatus.
The shielding structure may reduce radio waves to be emitted from the apparatus.
No prior arts have proposed an idea to reduce radio waves emitted from a printed board installed in an electronic apparatus. Instead, the prior arts have considered the electronic apparatus itself and have reduced radio waves emitted from the apparatus as a whole by entirely shielding it.
Some electronic apparatuses are not well shielded. For these, the radio waves must be reduced at the level of printed boards installed of in them instead at an overall level of each apparatus.
Although it has generally been understood that radio waves might be emitted from the edges of a printed board, no verification about it has been made yet. Therefore, no proposal has been made so far for a structure of reducing radio waves emitted from a printed board.